Calculating machine switch



J. L. MOODY 2,279,480

CALCULATING MACHINE SWITCH Filed March 4, 1940 I5 Sheets-Sheet l\NVENTOR John L. Moody 4 am e ATTORNEY J. L. MOODY 2,279,480

CALCULATING MACHINE SWITCH Filed' March 4, 1940 5 Sheets-Sheet 2INVEVNTOR /o/m Z. Maodg April 1 4 1942.

ATTORNEY April 14, 1942, MOODY 2,279,480

CALCULATING MACHINE SWITCH Filed March 4, 1940 5 Sheets-Sheet 3 a a R aa W m H \N a? EU i u EM R W- Q m a m ml lr m Patented Apr. 3 '14, 1942UNITED STATES PATENT OFFICE 2,279,480 CALCULATING MACHINE swrrcn John L.Moody, Oakland, Calif., assignor to Friden Calculating Machine 00.,Inc., a corporation of California Application March 4, 1940, Serial No.322,092

1 Claim.

This invention relates to calculating machines or the like and isconcerned more particularly with the provision of improved circuitcontrol means for such machines when driven by direct current motors.

It is a general object of the invention to provide improved means forreversing the current in a direct current circuit of a motor-drivencalculating machine or the like.

Another object of the invention is to provide a device of the characterreferred to, wherein the reversing of the circuit is controlled by anoperating control of the calculating machine.

Another object of the invention is to provide an improved reversingswitch.

Other bjects and advantages will appear from the following descriptionof a preferred embodi-.

ment of the invention as illustrated in the accompanying drawings, inwhich:

Figure 1 is a sectional elevational view of a calculating machine withwhich the instant invention can be employed.

Figure 2 is a fragmentary rear elevational view of the polarityreversing switch as mounted in the calculating machine.

Figure 3 is a view similar to Figure 2 showing the parts in anintermediate operating position during a reversing operation.

Figure 4 is a rear elevational view similar to Figure 2.

Figure 5 is a sectional elevational view of the reversing switch showingone operating position thereof. The section being indicated by the line5-5 of Figure '7.

Figure 6 is a sectional elevational view similar to Figure 5 showinganother operating position thereof.

Figure 7 is a vertical transverse sectional view taken in a planeindicated by the line 1-1 in Figure 5.

Figure 8 is a horizontal sectional view taken in planes indicated by theline 8-8 in Figure 6.

Inelectrical devices such as calculating machines, for example, havingdirect current driv ing motors which are started and stopped by means ofa pair of make and break contacts, mantaining the polarity of thecircuit in a given direction causes a build-up on one of the pair ofcontacts and a corresponding erosion of the other contact, as a resultthe contact surfaces become irregular and require frequent servicing orreplacement for satisfactory operation. In accordance with the instantinvention the foregoing disadvantages are eliminated by the provision ofmeans for periodically reversing the polarity of the circuit. In thisway the metal is first deposited on one contact and then on the other,with sufficient frequency to prevent an undue build-up and to maintainthe contacts in good condition over a long period of life.'

The invention may be employed for example in a calculating machine ofthe type disclosed in the copending application of Carl M. Friden,Serial No. 35,619, filed August 10, 1935, for Calculating machine.

Referring to Figure l, the calculating machine may include a base I0upon which the frame including a side plate H is mounted. A shiftableregister carriage I2 of the usual construction may be provided. Thedriving mechanism for the calculating machine may include a directcurrent electric motor l3 having a drive shaft l4 connected by gearing15 with a cyclically operable clutch :1, providing a cyclic drive for atransverse drive shaft M3. The clutch I! may be controlled by a lever i9operated through a slide 2| suitably mounted on the frame for endwisemovement and adapted to be operated by suitable control means forexample by keys 22 or by a control lever 23 for an operation such asdivision.

For opening and closing the motor circuit simultaneously with thedisengagement and engagement of the clutch, the slide 2| is connected bylever 26 with a pivoted lever 21 having an insulated pin 28 overlying acontact 29 adapted for engagement with a second contact 3|. Contacts 29and 3| are placed in the motor circuit in any convenient manner tocontrol the energization thereof.

the division lever 23 in a counterclockwise direction as viewed inFigure 1, slide 33 moves to the right and rocks bellcrank 35 andbellcrank 39 to operate slide 2| and thereby engage the clutch and movecontact 25 into position to energize the motor. At the same timeinsulated roller 42 upon slide 33 engages an end of contact arm 31 tomove contact 3! away from contact 29 and thereby prevent energization ofthe motor until release of the division lever 23. The slide 33 and thedivision lever 23 are restored to normal position' upon release of lever23 by spring 63 connected to slide 33. Thus division lever 23 has asetting or conditioning movement during which the machine is conditionedfor operation. and a further movement to actually start the operation byenergizing the motor. During the setting movement of division lever 23,bellcrank 38 also operates through pin 46 to rock arm and shaft receivearm 49.

Slide has a pin 56 on which is pivoted an operatin'g pawl 51 having aV-shaped lower nose 51A and a V-shaped upper nose 51B for centeringengagement with the lower pair of rollers 52.

The slide 5| is urged to its raised position by spring 58 extendingbetween pin 56 and stop pin 59 on bracket 53. From the foregoingdescription it will be seen that each time the division lever 23 isoperated'the slide 5| and its pawl 51 will be moved downwardly. Thismovement is used to control the reversing movement of an insulatedcontact member, carrying the reversing elements of the switch.

Referring to Figures 5 to 8, the reversing switch may comprise a pair ofopposed blocks GI and 62 formed of suitable insulating material such asBakelite. Blocks 6| and 62 are held between similar retaining plates 63and 64, also of insu-, lating material, by suitable fastening studs 66.Blocks 6i and 62 are cut away at their facing surfaces to provide aspace 61 in which the reversing contact element is positioned as laterdescribed.

As seen in Figures 7 and 8, the block 62 ca ries vertically spaced apartinput terminals ll, 12 mounted in suitable recesses in the block 62 andretained therein by plate 64. Each terminal is recessed to receive aspring urged contact '13 associated therewith and having a reduced endprojecting into the space Bl. Similarly, the block 61 carriestransversely spaced output terminals l6 and Ti, also having spring urgedcontacts 73 associated therewith and projecting into the space 61.Preferably, terminals 76 and TI lie in the same arcuate line as contact12 with respect to a pivotal axis 82 referred to hereinafter. To

arcuate portion 86 to the right of nose 84 as shown in Figure 3.Subsequently, pawl 51 will rock element 83 in a clockwise direction tocarry the centralizing nose 88 past the center of the note ofcentralizing pawl 89 whereupon the spring 9| becomes effective tocomplete the rocking movement of the member 83. When pawl 51 issubsequently retracted, its point is operatively related to theleft-hand side of the V- shaped. nose 84 on element 83, so that asubsequent depression of the pawl 51 will rock the element 83 in acounter-clockwise direction, that is back to the position shown inFigures 2 and 6.

In order to control the reversing of the circuit by the rocking movementof the 'reversing element 83 such element is provided with two sets ofthin contact strips of suitable conducting material, such as beryllium,to make contact as desired in its two positions. For .example as seen inFigures 5 and 6, one pair of contact strips 86 is provided having aslightly arcuate shape, while another pair of V-shaped strips 91 areprovided. The strips of each pair are similar and are riveted toopposite sides of the element 83 by rivets 89 to be electricallyconnected to each other to form an electrical conducting lead. Ifdesired, the element 83 may be provided with an aperture 98 of irregularoutline to provide air gaps between contacts 96 and 81. Contact strips96 and 91 both have a pair of rivets 99 in the arcuate line of terminalsl2, 16, TI, and

spaced apart a distance equal to the spacing of terminals 16 and I1 fromterminal 12. Contact strips 96 and 91 also both have a rivet 99 mountedfor movement in an arcuate line including 7 terminal ll and adapted foralternative engageinput terminal 12 with output terminal IT, and

provide a mounting for the reversing contact element, block 62 (Figure'7) has an upstanding boss 8| carrying a pivot stud 82 for the reversingcontact element 83. The reversing element 83 may be formed of some wearresistant insulating material. for example, Micarta.

As shown in Figures 5 and '7, the oscillatable reversing element 83 hasat its upper end a V- shaped nose 84 and a pair of arcuate sockets 86adjacent thereto. Nose 84 presents cam surfaces for engagement with pawl51 to enable back and forth actuation of element 83. Spaced apart guides81 are provided at either side of the ele ment 83 to receive the pawl 51to prevent lateral deflection thereof. To control the rocked posi tionof the element 83 a V-shaped centralizing nose 88 is provided thereonfor cooperation with I a suitable centralizing lever 89 pivoted betweena contact point lying in a second arcuate path strips 91 serve toconnect input terminal H with output terminal 76. With the reversingelement adjusted as seen in Figure 6, the input terminal II is connectedto the output terminal 11 and the input terminal 12 is connected to theoutput terminal I6 so that the polarity of the circuit is reversed fromthe condition shown in Figure 5.

It will be noted that because the element 83 is operated by theactuating pawl 51 while the contacts 3| and 29 are open that no arcingcan occur because of such reversal, but that the reversal always occurswhile the circuitis dead.

I, therefore, claimas my invention:

In a polarity reversing switch, a reversing switch member mounted forlimited rocking movement about an axis between two end positions, twopairs of terminals operatively related to said member, one terminal ofone pair being disposed in an arcuate path about said axis with bothterminals of the other pair,'and.a

pair of circuit making leads mounted on said member, each lead having apair of contact points disposed in said path for connecting said oneterminal of said one pair with'a terminal of the other pair, and each ofsaid leads having JOHN L. MOODY.

